1. Field of the Invention
This invention relates generally to psychiatry and psychology and specifically to detection and evaluation of individuals having near-term suicidal risk, to facilitate treatment of such individuals and to prevent suicide.
2. Description of the Prior Art
Current techniques for assessing suicidality in patients include clinical interviews, history-taking, assessment of current stressors and family evaluations. Structured questionnaires, such as Beck Inventories, are used as well as nonstructured projective psychological tests.
Paradoxically, optimal assessment of risk calls for extremely time-consuming integration of relevant information from numerous sources by experienced clinicians and/or crisis teams in situations usually requiring immediate judgments so that patient protection and support can be provided. While brief screening methods and scales are available, they rely heavily on known demographic, historic and diagnostic risk factors derived from epidemiological studies which may have limited specificity and utility in prediction of near-term suicidal risk.
Authorities on the front-line, namely clinical family practitioners, police, nurses, crisis/hot-line volunteers and first year residents in non-teaching hospitals or outside teaching hospital settings, are repeatedly called on to make rapid judgments involving responsibility for identifying persons at risk for suicide. This is despite their limited access to the most relevant information and being without sufficient knowledge, training or access to more experienced clinicians. There are times when an individual, such as a police officer, has little else but the heard voice of the patient to tell him or her what action the speaker patient intends.
There is a pressing need to identify characteristics of individuals in near-term suicidal states. Suicidologists have recognized the need for investigation of state-dependent features of mental illness in order to improve near-term prediction and specificity of prediction of suicidality.
Suicidal persons' communications may take the form of direct admissions of intent, denials, ambiguous complaints or apparently superficial chat. Too often these communications fail to signal the extent of the danger. Results of psychological autopsies reveal that from forty (40) to sixty (60) percent (%) of patients who completed suicide had consulted a physician within the prior month and had communicated suicidal thinking to friends and family.
Most people who kill themselves have recently told others or intimated what they were thinking of doing. Such communications may be straightforwardly direct or may be more subtle, namely cloaked in somatic complaints or making only general reference to frustration and distress. In such cases, what is said diverts the listener from the emotional state of the speaker and is not heard effectively by the listeners in whom the suicidal person confides.
Historically, psychoanalysts and psychodynamic psychotherapists have been concerned with the ways psychological states can be communicated by vocal behavior independent of content. The necessity of “listening with the third ear” is a well-established principle in clinical evaluation and psychotherapy. This form of listening requires a special quality of attention, so that the clinician is alert not only to unconscious and preconscious verbal meanings but also to emotional resonances and predispositions to certain types of behavior. A clinician's attunement to these paralinguistic communications is essential to rapport and empathy with the patient, to facilitate timely intervention. A recognized analogy for this exchange is a mother's responsiveness to different internal states conveyed by her infant through changes in the infant's cries and other vocalizations.
This special form of listening requires an awareness in the clinician of his own defense-driven efforts to not hear and to ignore emotional meanings encoded in patients' non-linguistic expressions. This need not to hear, while accented in the therapeutic situation, is ubiquitous in human interchange and assumes a special significance when listening for suicidality. Vocalizations in danger situations are biologically programmed to elicit responses of rescue and support by the listener. However, suicidal speech often triggers a need in the listener not to hear the communication of end stage despair. This maladaptive response may arise in part from an unconscious collusion with a patient's conviction that he is already terminal and beyond the reach of intervention.
Other factors may block effective listening. People differ widely in their sensitivity to the attributes of pitch, prosody and voice quality, all of which are involved in the detection of emotional cues in speech in general and in suicidal speech in particular. Musicians typically demonstrate the auditory acuity and differentiation required to bring information about effect or vocal signatures into the foreground; other groups of people may not have such auditory acuity.
Numerous studies have correlated suicide attempts and completed suicides with depressive disorders. While early studies indicated that clinical depression may substantially increase the probability of completed suicide, later studies provided statistics indicating that high suicide risk and rates, unlike originally assumed, was not to be equated with affective disorder but could be found in an otherwise heterogeneous group of psychiatric patients. These studies further showed that in depressed patients the overall severity of depression did not differentiate between suicide attemptors and non-attemptors, suggesting that some other, additional factor(s) were involved in determining suicide risk.
Studies of the vocal parameters associated with psychomotor retardation have documented the “loss of power over the course of an utterance” and “talking down the breathstream” as being synonymous with increases in duration of pauses.
Monopitch and monoloudness are among the depressive parameters which have been studied as relevant to the diagnosis of depression and the measurement of a patient's improvement.
Researchers have described the reduced prosody, lack of intonation, restricted pitch patterns, narrowing in pitch range and monotonous voice quality observed in depressed persons. Over fifty years ago researchers described “leaden, expressionless” features of the voices of depressed patients.
Prior investigators have underscored the need to examine differences in the psychological structures driving vocal phenomena which appear to be very similar to each other but prove, on closer scrutiny, to be clinically and acoustically disparate as well. Studies bearing on the connection between vocal parameters and clinical states have examined differences between the flat, hollow, monotonous voice of the schizophrenic patient and a comparable vocal flatness in depressed patients. Upon closer scrutiny the depressed person's flatness was found to be reflected in pauses and loss of power over the course of sentences.
Both of these are consistent with psychomotor retardation. The voices of schizophrenic patients demonstrate a lack of emphasis which researchers have found is related to the absence of word imagery, providing a critical example of the impoverished capacity for internal representation characterized by schizophrenia.
Additional studies have found that schizophrenics with negative symptoms demonstrate a decrease in the intensity of their speech at higher harmonics. With increasing depressive symptoms, schizophrenic subjects were found to have moved from normal timbre and normal intonation to an expressionless flatness in their speech.
Still additional studies have postulated the existence of a high correlation between panic disorder and suicidality.
Researchers speculating on the promise of speech research have suggested that the only structures in humans evolved specifically for speech are small areas at relatively high levels of the central nervous system. The integration of the complex behavior of speech is, so to speak, imposed from the top. Perhaps because of this, speech is sensitive to subtle, clinically important changes in a patients state.
High near-term suicide risk has been described as a meta-critical state, self-sustaining, highly autonomous and independent of whatever originally brought it about. Researchers have observed that the whole notion of such an autonomous inner state is closely related to phenomena such as shock and anaclitic depression.
Clinicians have recommended that suicidality be formally designated as an independent entity co-morbid with a range of diagnostic groups. Some believe that assessment and treatment of suicidal persons is best conceptualized not in terms of psychiatric nosologic categories, but rather in terms of psychological pain and thresholds for enduring that pain.
Prior researchers, with the benefit of the teachings of U.S. Pat. No. 4,675,904 (issued in the name of one of the instant inventors), have stated that the most significant information relevant to both the speech characteristics of affectively disturbed patients and the individual sound characteristics (usually referred to as “timbre”) of human voices is encoded in the distribution of overtones in spectral patterns and corresponding variabilities. These same researchers further state that depressive profiles rely too heavily on scalar parameters addressing speech flow, loudness or a speaker's dynamic expressions and do not tap into the temporally varying manifold timbres of human voices.
Suicidal crises during treatment and prevention efforts are often described by clinicians as the single most anxiety-increasing problem for them. Potentially dangerous for the patient and harrowing for the clinician, these episodes can compromise a clinician's judgment, undermine the foundations of a working alliance or lead both clinician and patient to violate the boundaries of treatment. In addition, knowledge of risk factors for suicide is based largely on studies that have examined the distinguishing characteristics of those people who, out of a group of individuals, kill themselves during a fixed time period, irrespective of what treatment may have been provided. Such studies actually identify factors which predict the risk of suicide in spite of treatment.